Preheat oven to 375°F. Line a baking sheet with parchment paper.
In a blender or using an immersion blender, puree tomatoes into a sauce.
Roll out one biscuit into a 5- to 6-inch round. In the center, place 2 teaspoons sauce, 2 tablespoons mozzarella, and 1/2 tablespoon pepperoni. Carefully fold over and press edges together with a fork. Place on prepared baking sheet.
Repeat with remaining biscuits until you have 8 pepperoni pizza pockets.
Bake for 20 minutes or until golden brown.
Meanwhile, simmer remaining sauce in a small saucepan over medium heat until thickened slightly. Serve homemade hot pockets with this warm sauce.